Field of the Disclosure
The present disclosure is generally directed to micro welding, and more specifically to technologies and techniques for attaching components, such as wire, using controlled removal and fusion of material using energy such as laser applied in the disclosed exemplary manners to strip, weld and cut fine gage wires to connection points in a single operational step.
Description of the Background
The term “micro welding” typically refers to the precise placement of connective metals and the application of energy to form welds that may be less than 100 μm wide. Usually performed under a microscope for accuracy, the actual welding process in some cases may be similar to normal welding, but on a much smaller scale. In most high-volume industrial settings, micro welding may be automated, requiring little input from an operator, but some specialty or irregular welds may require a highly-trained technician.
Known micro welding techniques include resistance micro welding, flash micro welding, arc micro welding and laser micro welding. The practice of stripping and preparing insulated wires for the production of electronic devices is also known and widely practiced. A very large number of electronic devices, such as electric motor transformer inductors and the like, place special demands on the conductive wires and the quality of workmanship, since the wires typically are wound or overlaid in large numbers, must possess thin and highly durable coatings with adequate thermal conductivity, and provide adequate resistance to heat damage and insulation breakdown. While the wire coatings are designed to insulate and protect the wires, the coatings may be difficult to strip and prepare for effective attachment to other components, and/or require multi-step processes to both strip and prepare the wires, as referenced above.
A wide variety of coating-removal techniques have been devised and these removal methods include scraping, abrasive removal, chemical removal and burning or ablating with thermal sources including hot solder, flames and lasers. Each of these methods possesses certain disadvantages, such as scratching or nicking the wire. Thermal annealing of the wire may render the stripped wire more vulnerable to breakage as it is subsequently formed in preparation for soldering or welding. Typically, such preparation is performed by twisting or wrapping or clamping the stripped wire to a terminal prior to soldering. After attachment, the resulting connection may continue to be weak and less reliable.
In addition, special wire insulation materials have been developed to retract or burn off when exposed to molten solder. However, the wires in such instances remain at risk of damage from the solder itself, at least because the increased exposure time of the wire exposed during the solder stripping process. Further, as the insulation is removed by exposure to molten solder, a chemical reaction between the tin in the solder and the copper in the wire may degrade the mechanical strength and electrical conductivity of the joint. The drawbacks of the aforementioned insulation removal techniques are particularly present for very small gage wires, such as AWG 30 and smaller.
The above drawbacks are greatly increased for small gage wires because the volume of insulation coating material is large as compared to the underlying wire. Furthermore, the surface area of the wire is large compared to the volume of the wire, which increases the rate of chemical reaction with the solder and thereby risks loss of strength and conductivity during the attachment process.
In a conventional assembly process, even if there were no degradation of the wire by the stripping process, prior to soldering the prepared wire the stripped wire must be mechanically formed to attach it to a termination point, typically by winding the wire around the termination or securing by various clips or clamping attachments. The process of mechanically securing the wires requires additional process steps which add to the complexity, time and expense of the assembly process.
This present disclosure improves the process of attaching insulated ultra-fine wires by eliminating processing steps, reducing handling time, and achieving equivalent or better mechanical and electronic characteristics in the attachment process to known methods by employing systems and methods that are suitable for automation and high volume production.